218 



ONTOGENY AND SYSTEMATICS OF HSHES-AHLSTROM SYMPOSIUM 



tially formed with gradual lengthening of gut, well developed 

 preanal finfolds and apparently precocious anal fin rays. Ad- 

 ditionally, during ontogeny eye shape changes from ovoid to 

 round, and body pigmentation changes from light to dense. 

 These larvae are too similar in general appearances to determine 

 trenchant characters that define genera or tribes. Peritoneal pig- 

 ment sections, are of prime importance in identifying early stages, 

 but show extreme variability with respect to their number and 

 sequential development. Of particular interest in this connection 

 is Notolepis. N. rtssoi develops 1 2 pigment sections, the largest 

 number in the family except Stemonosudis (3 1 ), whereas the 

 Antarctic congener, TV. coalsi, has only a single section which 

 increases in size with growth (Efremenko, 1978, 1983a). Among 

 the various genera the primary section develops at 5-10 mm 

 and full complements are formed variously by the species be- 

 tween 15-45 mm. Usually, metamorphosis takes place around 

 this size accompanied by the development of a black perito- 

 neum. 



In addition to the exceptionally higher number of pigment 

 sections, Stemonosudis is peculiar in having a filamentous pro- 



jection on the lower jaw tip (in larvae of 5. macrura and in 

 juveniles and adults of S. intermedia and 5. elongatd). Likewise, 

 Uncisudis (=Pontosudis) uniquely develops an elongated pelvic 

 fin. 



Patterns of melanophores are extremely diverse but of use in 

 identifying species or species groups; pigment patches on the 

 caudal peduncle, dorsum of body, and caudal and pectoral fins 

 are particularly important. Rofen (1966a) suggested that the 

 single larval character discriminating the two tribes in Parale- 

 pidiinae, i.e., Paralepidiini and Lestidiini, is whether the rear- 

 ward shift of the anus occurs early or late in ontogeny. 



Incertae ce^w. — Peculiar eggs described by Delsman (1938) and 

 Mito (1961a) are currently considered to be those of mycto- 

 phiform fishes other than Myctophidae (Moser and Ahlstrom, 

 1970). These eggs are spherical, 1.12-1.37 mm in diameter, with 

 a single oil globule and bear numerous short appendages on the 

 chorion. Two types are known only from Asian waters. 



Ocean Research Institute, University of Tokyo, 

 MiNAMiDAi, Nakano-ku, Tokyo 164, Japan. 



1-15-1, 



Myctophidae: Development 

 H. G. Moser, E. H. Ahlstrom and J. R. Paxton 



LANTERNFISHES of the family Myctophidae are found in 

 all oceans of the world. Some 230-250 species are arranged 

 in 36 generic/subgeneric taxa (Table 59). All nominal species 

 are listed in Paxton (1979). Characteristic of the family is the 

 presence of light organs or photophores on the head and body 

 (Fig. 1 1 4). The different patterns of photophores have been used, 

 along with meristics (Table 60), in species diagnoses and as a 

 basis for classification within the family since the late 1800's. 

 Most authors have placed the Myctophidae and closely related 

 Neoscopelidae with the families Aulopidae, Chlorophthalmidae 

 and related families in an order or suborder variously named 

 the Iniomi, Myctophoidea or Myctophiformes (Gosline et al., 

 1966; Greenwood et al., 1966; Nelson, 1976; Johnson, 1982), 

 although Rosen ( 1973) separated the Myctophidae and Neosco- 

 pelidae as a restricted order Myctophiformes. Moser and Ahl- 

 strom (1970, 1972, 1974), Ahlstrom et al. (1976) and Paxton 

 (1972) are the most recent papers considering relationships with- 

 in the family; characteristics of larvae and bones and photo- 

 phores of adults were primarily utilized in the respective studies. 

 Paxton's (1972) classification, including genera recognized sub- 

 sequently, is as follows: 



Subfamily Myctophinae 

 Tribe Electronini 



Genera: Protomyctophum. 

 Metelectrona- 



Krefftichlhys', Elect rona. 



Tribe Myctophini 



Genera: Benthosema, Diogenichlhys, Hygophum, Myc- 

 tophum. Symbolophorus 

 Tribe Gonichthyini 

 Genera: Loweina, Tarletonbeania, Gonichthys, Centra- 

 branch us 

 Subfamily Lampanyctinae 

 Tribe Notolychnini 



Genus Notolychnus 

 Tribe Lampanyctini 



Genera: Taaningichthys, Lampadena, Bolinichthys. Lep- 

 idophanes, Ceratoscopelus. Stenobrachius, Lampan- 

 yctus, Triphoturus, Parvilux^ 

 Tribe Diaphini 



Genera: Lobianchia, Diaphus, Idiolychnus* 

 Tribe Gymnoscopelini 



Genera: Lampanyctodes, Gymnoscopelus, Notoscopelus, 

 Lampichthys, Scopelopsis, Hintonia 



There has not been a family revision at the species level since 

 Fraser-Brunner's (1949) study. A large number of more recent 

 generic revisions and regional studies are currently the primary 

 sources for species identifications; most of these have been uti- 

 lized in compiling the generic distribution limits (Table 59). The 

 most recent zoogeographic studies are those of Backus et al. 



Hulley (1981). 

  Wisner(1963). 



' Hubbs and Wisner (1964). 



" Nafpaktitus and Paxton (1978). 



